docs: def cli(env, volume_id, replicant_id, immediate):
      """Failover a block volume to the given replicant volume."""
      block_storage_manager = SoftLayer.BlockStorageManager(env.client)
  
      success = block_storage_manager.failover_to_replicant(
          volume_id,
          replicant_id,
          immediate
      )
  
      if success:
          click.echo("Failover to replicant is now in progress.")
      else:
          click.echo("Failover operation could not be initiated.")